Transcript for DNA evidence clears Kevin Fox of his daughter’s murder: Part 6
MM, I haven't seen these boxes, I would say, for probably 10 years. 3-year-old Riley fox was taken from her home in the middle of the night. It brings back a lot of memories about the criminal case, the civil case, everything. It's just such an incredible story. After an all-night interrogation, police and prosecutors gathered to announce Kevin fox had confessed. Most of us say, I would never confess to something I didn't do. People would be surprised. Police interrogation unfolds in two stages. The first stage is about reducing a suspect to hopelessness. I denied the whole thing all night and said I didn't do it, I didn't do it. And they would not believe me. They'd go back and forth between promising and threatening. It's a classic case of a false confession. When you're done filling this out, if you don't admit you murdered your daughter, you're getting 30 years to life. Kevin and Melissa agree to actually re-enact the interrogation as best as they could remember, what it was like inside that room. Listen to me! You You killed your daughter. Child killer. The will county sheriff's department, they dispute what Kevin fox said went down in there. I didn't kill my daughter though. Yes, you did! Kevin fox was questioned for 14 1/2 hours. We see this commonly in false confession cases. That's not by accident. It only adds to the suspect's desire to get out of that room. I was exhausted. I had guys yelling at me, saying I was going to get raped. I told him, I know people in prison that will rape you every day. The detectives and that sergeant, they deny that they ever threatened Kevin fox during that interrogation. And there was something else that they denied. They denied ever showing Kevin a crime scene photo of his dead daughter. And they showed me the picture of Riley in the creek, dead, bound, mud on her face. That was just the breaking point. The fact that he had to actually see it just breaks my heart for him. Now this goes on and on and on until another ruse happens during this interrogation. An officer rushes in and says, I've just spoken with one of the prosecutors. It's just going to be like a misdemeanor, involuntary manslaughter. You can get out on bond. Everything will be okay. If you say that you did it, they can work out a deal for Yu. Those are the words that led him to give the statement he gave. Some of the sheriff's investigators actually acknowledge that they did discuss involuntary manslaughter with Kevin fox. They said they made no promises. By the time Kevin fox confessed, it was about 8:00 in the morning. He'd been awake for more than 24 hours. I pretty much went along with their story to get out of there. Now police say fox has given a deotaped statement implicating himself. These are really powerful psychological tactics. They are very good at getting confessions from guilty people, but they're so powerful that they can also cause the innocent to confess. I would never in a million years prosecute a case with only one piece of evidence and that one piece of evidence being a confession. I need confession plus DNA. Confession plus fingerprint analysis. A whole array of other bits and pieces of evidence to corroborate the confession. A confession isn't magic. It's a piece of evidence just like any other piece of evidence. You have to test it against what you know, against what the facts tell you happened in this case. It's the worst hand you can be dealt as a defense attorney, because jurors are going to convict somebody who's confessed to something unless you've got DNA evidence. Remember something with Kathleen Zellner -- DNA is how she has been able to free people, to get them exonerated. They did get some genetic material from Riley. The DNA was collected. Two days after the toddler's body was found in a creek near Wilmington. The problem is, five months later, it still hadn't been analyzed. In November, then, Jim Glasgow defeated Jeff tomzcak and took over the state's attorney's office. After Glasgow came in, there was that DNA evidence that had been sent to the FBI and had been sitting there was recalled. They said send it back to us. That DNA evidence was sent out to a private lab. They're pinning their hopes to the DNA test, hoping they might prove his innocence before the case ever goes to trial. He knows he's innocent. I know he's innocent. The answers, like we say, lie in the DNA testing. Bear in mind, if that DNA analysis had come back as Kevin, it was game over. He was going to be on death row. It makes all the difference. It makes all the difference. Test results arrived last night. The DNA did not match Kevin fox's. They came back and said, this is not his DNA. We can't tell you whose it is, but we can tell you it's not I never expected the DNA results to come back in this fashion. We were shocked at the results. Glasgow sees this. To his credit, does the right thing. I said, well, there's one thing that's certain to me, I can't prove this case beyond a reasonable doubt. And the moment that I reached that decision, I cannot continue to prosecute that person. And that's when he said to me, I'm going to release him tomorrow. Kevin fox is free after prosecutors concede there is now considerable doubt about his guilt. Prosecutors dropped all charges against the Wilmington father. It was a nightmare, and I don't want to relive it right now. I don't want to -- I'm happy. If you want to take away one thought in this case, it's do the task before you make the arrest. Even after I got out of jail, I still had people coming up to me and saying I was a child killer, a child molester, and threatening to shoot me and my dog. This was after the DNA. After the DNA, after I got out of jail. Kevin fox is ruled out. This is a game-changer. Now you have to refocus this investigation. The DNA proves that you didn't do it. But then the question becomes, who did? And then the other question becomes, what else may have gotten missed, left out? Witnesses reported seeing a strange red car parked right in front of the fox's home. When we found out that they had the killer's shoes in evidence and had never pursued that, it's like, wow, all this time, right there.
This transcript has been automatically generated and may not be 100% accurate.